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Although we're a long way from New Year's resolutions, summertime sometimes motivates us to start exercise programs (with apologies to our readers in the winter of the Southern Hemisphere). The length of daylight and time for vacations seem to prod many of us to get outdoors and break a sweat more often. As a result, you might also be thinking more about your nutrition.

For example, we all know that consuming protein is required to build muscle mass. But how much?

In the U.S., the current recommendation is for 0.8 grams of protein daily for each kilogram of your body weight, or 0.36 g/pound. That's about 71 grams a day for the average 196-pound U.S. man, or 60 grams for the average 166-pound U.S. woman (average weights for U.S. adults ages 20 and up – yes, I'm surprised they're so high – are from this report).

However, some physicians and physiologists find this to be an underestimate of what we truly need. The reason is that the so-called recommended daily allowance (RDA) is based on the minimum needed to prevent the loss of lean body mass. So, the average adult may need more than 60-70 grams of protein per day. In fact, the amount needed by elderly individuals is even greater than that of those most commonly studied dietary subjects: college-aged men.

Robert R. Wolfe, Ph.D., now director of the Center for Translational Research in Aging & Longevity at Texas A&M University, gave such a concise argument with colleague, Susan L. Miller, Ph.D., in this 2008 viewpoint piece in JAMA. They argued then that the RDA should really be renamed the minimum daily requirement, a term previously used for other nutrients, to reflect that greater amounts are more meaningful for the average adult. Subsequent work has suggested that these numbers should be raised anywhere from 20% to 50%.

But, I know – I'm not helping you with your own dietary goals. What does this all mean?

30 grams of protein at every meal

Consuming a meal with 30 grams of high-quality protein has emerged as the average consensus from studies designed to maximize muscle protein synthesis across people of various ages, body mass, and activity levels. So that would be 90 grams a day for most of us.

But most Americans don't split their protein intake equally across their three meals. Do you? The majority of us tend to eat about three times more protein at dinner than we do for breakfast.

A mix of high-quality proteins for breakfast might very well be good for your muscles. (Photo credit: Wikimedia Commons, user Rjh1962)

In a new paper published in the Journal of Nutrition, researchers asked a simple question, assuming that a total of 90 grams per day would be best: Would human subjects make more muscle protein if their optimal intake was evenly split across the three meals when compared with typical protein intake patterns skewed toward a protein-heavy dinner?

The study was conducted with a group of five men and three women between ages 25 and 55. The subjects were physically active, but not athletically trained, averaging 32% body fat and with an average body mass index in the normal range.

The research team was led by Douglas Paddon-Jones, Ph.D., at the University of Texas Medical Branch in Galveston and Donald K. Layman, Ph.D., at the University of Illinois at Urbana-Champaign, and the paper's primary author was Madonna M. Mamerow, Ph.D., a postdoctoral research fellow at UTMB-Galveston.

While the sample size is quite small as compared with drug trials, these sorts of nutritional studies require intense participant commitment in adhering to strict diets, having multiple blood draws in two 36-hour inpatient hospital stays, and multiple muscle biopsies – a total of 12, across the two phases of the study.

But these smaller studies allow conditions to be very tightly controlled, and it's worth taking a moment to examine how the researchers minimizing any confounding variables. Each subject received both diets for seven days with a 30-day washout period between the two. One was, as I said earlier, a roughly even 30 grams of protein at each meal. The skewed diet consisted of 10 grams at breakfast, 15 grams at lunch, and 65 grams at dinner.

These diets were a mix of foods with high-quality protein and not any sort of protein supplement.

Muscle protein synthesis was measured by injecting the participants with a specially-tagged version of the amino acid, phenylalanine, waiting 24 hours, then taking samples of one of their thigh muscles. The researchers did this metabolic study on the first day and then again after the volunteers spent seven days on the diet.

To ensure that any changes were due to the diet alone and not muscle repair after exercise, the participants were instructed to avoid strenuous physical activity for the three days preceding each metabolic study. But the volunteers were permitted a 30-minute, moderate-intensity treadmill walk during each inpatient stay to avoid any artificial issue with 36 hours of complete bedrest for the metabolic study.

The researchers found that muscle protein synthesis averaged 25% higher when participants ate the evenly-divided protein diet than when on the diet skewed toward a protein-rich dinner. The difference was even observed as early as the breakfast meal where 10 grams was eaten on the skewed diet and 30 grams on the even diet. Most noteworthy was that this benefit of the evenly-divided protein diet persisted after seven days, suggesting that the body doesn't simply accommodate to the continuous protein intake.

Again, while a small study with eight participants, the research design benefitted from the strength of using each participant as their own control since each was subjected to both diets, 30 days apart. The technical aspects of the study appear to be very well executed as evidenced by the very small statistical variability in the measurements–in my lab days, we'd call these data "tight."

The authors write that the results are consistent with what we know about dietary intake:

"Unlike fat or carbohydrate, the human body has limited capacity to transiently store 'excess' dietary protein from a single meal to acutely stimulate muscle protein anabolism at a later time."

In an accompanying editorial, University of Connecticut nutrition professor, Nancy Rodriguez, Ph.D., writes:

"The unique contribution of this work is the assessment of the skeletal muscle protein synthetic response for a 24-h period, taking the finite single acute measure typical of most skeletal muscle protein fractional synthetic rate assessments one step further."

One disclosure note: The study was funded in part by the Beef Checkoff Program of the Cattlemen's Beef Board together with federal funding from the National Institute on Aging and the National Center for Research Resources. Dr. Paddon-Jones and Dr. Layman also disclosed speaking fees from the National Cattlemen's Beef Association.

The cattle industry funding is common in the nutrition field. These days, you can't do this kind of academic research with NIH funding alone. Even the editorialist, Dr. Rodriguez, disclosed speaking fees from the NCAB and National Dairy Council. But I mention it because an examination of the study diets reveals that the animal protein sources for the skewed diet were pork, chicken, and chicken eggs, while the superior, evenly-distributed diet included beef, cow milk, and turkey. My enthusiasm for the study design would have been greater if a mix of animal proteins were represented in both diets.

Conclusions

Rodriguez did caution that "translating research findings into evidence-based dietary guidance . . . is an elusive pursuit."

In fact, both she and the authors noted that one limitation of the study – and of any study like this, is that one is examining a snapshot sum of muscle protein synthesis and breakdown. So we don't know precisely that the 25% increase in muscle protein is due solely to increased protein synthesis or a slowdown in muscle breakdown. Technically, the distinction would required another type of protein tagging and a separate set of muscle biopsies.

But these types of studies are the best we can do with today's technologies. I, for one, have started to shift my protein consumption, especially increasing how much I take in at breakfast. A high-protein, Greek-style yogurt gives me 12 grams of protein and a large bowl of a whole grain cereal with some low-fat milk gets me another 18.

Dr. Paddon-Jones speaks in general terms about the evenly-distributed protein approach in this video from the UTMB research experts' page.

For more health and pharmaceutical information, follow me on Twitter @DavidKroll, here at Forbes.com, or subscribe to my public updates on Facebook.